When dealing with the filling of capsules with pharmaceutical products in granules, a feeding assembly is known, which is of the type comprising a filling drum, which is mounted so as to rotate around a given rotation axis and is provided with a plurality of fillers distributed around the rotation axis; and a pocket conveyor, which is provided with a plurality of pockets, each designed to receive and hold a bottom of a respective capsule.
The granules are housed inside an annular containing hopper, which has a longitudinal axis, which is parallel to and distinct from the aforesaid rotation axis of the filling drum.
Each filler comprises a suction pipe, which can be connected to a pneumatic sucking device and is coupled to the filling drum so as to carry out, relative to the filling drum, straight movements parallel to the rotation axis.
Each suction pipe is provided with a thin plate, which is fixed in an intermediate point of the suction pipe, so as to define a lower filling chamber, whose volume depends on the position of the thin plate along the suction pipe.
The thin plate has a plurality of openings, which allow the filling chamber to be connected to the pneumatic sucking device and are designed so as to prevent the granules from moving forward along the suction pipe.
The suction pipes are fed by the filling drum along an annular path, which extends around the aforesaid rotation axis and comprises a first portion overlapping the hopper and a second portion on the outside of the hopper.
In the area of the first portion, each suction pipe is firstly lowered into the hopper so as to suck a corresponding quantity of granules into the filling chamber and is then lifted to disengage the hopper.
In the area of the second portion, each suction pipe is lowered on the relative bottom so as to release the granules contained in the filling chamber into the bottom.
Since, at the outlet of the hopper, each feeding pipe holds back a quantity of granules that is greater than the volume of the relative filling chamber, the granules projecting out of the filling chamber must be scraped by means of a scraper and recirculated again inside the hopper.
The presence of the scraper and of the granule recirculation system in the hopper makes known feeding assemblies of the type described above relatively complicated and expensive.
Furthermore, the scraping process can jeopardize the integrity of the excess granules of each suction pipe and, in any case, leads to the recirculation and the handling of relatively large quantities of granules on the outside of the hopper.